That we’re living in a post-PC era is undeniable. Still unconvinced? Consider the following (courtesy of a recent Google/Ipsos OTX study): 79 percent of smartphone consumers use their phones as a shopping tool—and 74 percent of these shoppers make a purchase. More than a third of consumers who see a mobile ad visit a website, and nearly half buy something. And it’s not just about convenience on the go: Ninety-three percent of smartphone owners use their devices at home.

OK, so mobile is where it’s at. The problem is that if your company is like most, its website still caters only to desktop visitors. Yet users are five times more likely to abandon a site if it isn’t optimized for mobile use.

So, what’s the solution? Not surprisingly, there are a few ways to approach mobile optimization, but arguably the most compelling is responsive website design. Put simply, responsive design ensures your website provides an optimal viewing experience on any device, be it desktop, tablet, or mobile. It prioritizes ease of reading and navigation by dynamically readjusting site content and user interface elements according to size of the reader’s screen. In essence, it makes your site “device agnostic.”

To get a feel for how responsive design works, visit The Boston Globe’s website on your desktop and resize your browser window to various widths. Watch how the content and navigation respond to keep the site intuitive. The Boston Globe’s site is one of the largest responsive websites, and it really showcases how powerful responsive design can be, even in very content-heavy scenarios.

Sounds great, but what’s the catch? Actually, there really isn’t one. While responsive websites do cost more to develop than conventional websites, they eliminate the need to create and maintain separate websites for mobile and other devices (a far more expensive strategy in the long term).

According to the Pew Internet Project, 45 percent of adult Americans have a smartphone, and 25 percent own a tablet. With these numbers continuing to skyrocket, the question shouldn’t be, “How much will it cost me to mobile optimize my website?” It should be, “How much will it cost me if I don’t?”